Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 11: Quantum dots and wires: Transport properties I
HL 11.9: Vortrag
Montag, 26. März 2007, 17:00–17:15, H15
Random-telegraph-signal noise and device variability in ballistic nanotube transistors — •Neng-Ping Wang1, Stefan Heinze1, and Jerry Tersoff2 — 1Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg — 2IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598, USA
The last few years have seen remarkable progress in carbon nanotube field-effect transistors (CNFETs). High performance and even ballistic transport have been demonstrated, and there is increasing focus on integrating such transistors into operational device circuits. Device integration requires stable and uniform behavior of the individual transistors. However, all materials exhibit some low-frequency electrical noise; and such noise increases inversely with the system size, so it is important to develop a microscopic understanding of noise in nanotubes.
In field-effect transistors, charge trapping in the gate oxide is known to cause low-frequency noise and threshold shifts. Here we calculate the effect of single trapped charges in a CNFET, using the non-equilibrium Greens function method in a tight-binding approximation. We find that a single charge can shift and even rescale the entire transfer characteristic of the device. This can explain both the large ``random telegraph signal'' (RTS) noise and the large variations between nominally identical devices. We examine the dependence on both the thickness and dielectric constant of the gate dielectric, suggesting routes to reduce electrical noise.